You might put a 7 1/4" circular saw blade on the saw for the initial cut. Then put the 10" blade back on.

 

I know thousands of people have dealt with this before. But I can't figure out the right verbiage to find an answer googling. I need to install a zero clearance plate for my table saw. Of course, for the initial blade slot, most install the plate, turn on the saw, and raise the blade to cut through. My blade on my Dewalt doesn't sit low enough when fully retracted for the plate to sit flush. Do I need a spacer of some sort?

No.
Just run the bottom of the piece over the router table with 1/4" of a 1/4" straight bit exposed the length a saw blade would need to get started, about 4" to 6".
Any other method you have that could provide a similar small relief area will also work.

 

Thanks guys, both great ideas. Probably go the router…route? So I don’t have to change blades twice.

 

Clean the trunnion assembly on the table saw as it is very likely you have sawdust/scrap build up in the mechanism - a table saw blade always goes below the table and plate (which is how most folks leave the saw when done with an operation) - OR, you have the wrong sized blade, which is not very likely.

Using a 7-1/4" blade could make the zero tolerance goal void as the tooth pitch/blade thickness will likely be different - yes, you could measure and verify before trying that 7-1/4 option if they happened to have the same arbor size - but, that's not the real issue causing the blade to sit proud of the table.

 

Good thoughts. For what it’s worth, when it’s cranked all the way down, the blade is below the top of the table, not sitting proud. But, the stock insert is thinner than the MDF plate I am add. For example, when I sit the plate in, it only props up the plate like a quarter to a half inch. Regardless, it is long past time to give it a good cleaning, so I’ll do that regardless.

 

On my DeWalt dwe 7485 the blade is only about an eighth of an inch below the surface. That is the way they are made.
On my rigid ts2400-01 it sits about a quarter inch below the surface so it's not uncommon for the blade to be really tight to the top.
I use my saw blade out of my handheld saw which is a 7, 1/4 to make my inserts for both of Rigid and the DeWalt. This way I know that as I bring the blade up very slowly it will be properly centered in space. I get a near zero clearance insert. Since zero would mean the plate would not clear it would bind so with the normal blade pitch of the teeth there's about 20,000 of clearance on each side so just enough to hold the splinters in place and get you a great cut.

Yes changing the blade twice as a hassle but it's also a good time to go ahead and clean the blade while it's out there's a lot of different solutions on the market and different ways of doing it my solution for doing it is using the top of a bucket which will take a 10-in blade without a problem and a little bit of laundry soap and let it soap for a few hours and a brass brush looks like a new one I'm done frustrating thing is when it gets dull still looks like new.

Good luck on making your zero clearance insert. And when you're making them make multiples.

 

Routing a slot is safest.

I would tell you how I’ve handled this, but the safety police would come after me……

 

Speaking of safety , I'm unable to see how a blade protruding above table without being used to cut would be safe at anytime . Personally I wouldn't turn a saw on under those conditions .

 

Speaking of safety , I'm unable to see how a blade protruding above table without being used to cut would be safe at anytime . Personally I wouldn't turn a saw on under those conditions and disable the switch or cut the male end of the cord off .

True, BUT that's not his issue.

My blade on my Dewalt doesn't sit low enough when fully retracted for the plate to sit flush.

The plate is so thick, the blade hits it before it's sitting flush.
This is a common issue when making DIY throat plates.
Some use a smaller diameter circular saw blade, BUT they are most likely a thin kerf, UNLESS it's a dado blade.

 

QUOTE :
My blade on my Dewalt doesn't sit low enough when fully retracted for the plate to sit flush. Do I need a spacer of some sort?

You've sure lost me but that's ok . We often don't all speak the same language .

 

You've sure lost me but that's ok . We often don't all speak the same language .

LOL. True enough, but this can be easily explained.

The factory throat plate is 1/8" thick and the 10" blade lowers below the top of the table no problem.
The OP made his own throat plate DIY, that's 3/8" thick so even at the lowest blade setting, it will not lay flush on the table because the blade is preventing that.
The factory throat plate came with a slot for the blade.
His DIY throat plate doesn't have a slot, yet.
He can't raise the blade under power like you typically do to make the slot/kerf because the throat plate is not safely flush in the insert depression.
That's the issue before us.

A good suggestion was to sticky tape the DIY plate carefully and directly on top of the factory plate and raise the blade under power to make the new slot.
The new slot will now align correctly when placed in the insert.
OR replace the 10" blade with a 8" blade the same kerf width from a dado stack.
The smaller diameter blade will allow the DIY plate to sit flush in the insert, no problem.

 

If a 10" blade will not lower enough replace it with a smaller diameter blade with the same kerf width to make a starter kerf for the larger blade. You need to remove the original blade anyway to adjust the height of the replacement insert so you can use the fence to hold it down to make the the cut.